Pseudomembranous cystitis, an unusual condition associated with feline urine outflow obstruction: Four cases

Pseudomembranous cystitis in cats with presumed or confirmed mineralization: A retrospective study of 26 cases (2016-2021)

BACKGROUND

Pseudomembranous cystitis (PMC) in cats is a recognized disease, but concurrent mineralization is reported rarely and its outcome is poorly described.

HYPOTHESIS AND OBJECTIVES

Describe a population of cats with PMC and the prevalence of concurrent mineralization.

ANIMALS

Twenty-six cats with PMC.

METHODS

Medical records were retrospectively reviewed (January 2016 to December 2021). Cats with an ultrasound diagnosis of PMC were included. Clinicopathologic results, imaging, treatment, and outcome were reviewed.

RESULTS

All cats were male and 21 (80%) were diagnosed with urethral obstruction (UO). Five cats (23.8%) had positive urine culture (Staphylococcus felis, 3/5; Proteus mirabilis, 2/5) with a median urine pH of 8 (range, 6-9). All cats had ultrasonographic changes suggestive of mineralization. On ultrasound examination, 10 cats (38.5%) had pseudomembranes with acoustic shadowing suggestive of mineralization, 15 (57.7%) had changes indicative of ulceration, and 8 (31%) had changes compatible with of a urachal anomaly. Twenty-two cats received medical treatment, 4 underwent surgery (3 percutaneous cystolithotomy, 1 cystotomy). Twenty cats (77%) survived to discharge. Follow-up ultrasound examination indicated resolution of PMC in 6/7 cats, 4 had persistent hyperechoic bladder lining. Five of 12 cats with follow-up had a relapse of lower urinary tract signs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Pseudomembranous cystitis was diagnosed mainly in male cats with UO and imaging findings suggestive of mineralization were present in all cases. Frequent negative urine culture suggests a different etiology than encrusting cystitis related to urease-positive bacteria. Good outcomes can be achieved with medical management.

Bladder wall adhesion causing a vesicular septum in a dog following surgical cystotomy

CASE DESCRIPTION

An 8-year-old spayed female Yorkshire Terrier-Poodle dog was evaluated for persistent pollakiuria and stranguria following routine cystotomy for calcium oxalate cystoliths.

CLINICAL FINDINGS

The dog presented for a cystotomy with intermittent hematuria. Postoperative radiographs revealed no remaining cystoliths. Urine, cystolith, and bladder mucosal aerobic cultures were negative. Pollakiuria, stranguria, and hematuria developed immediately after surgery and persisted despite antibiotics. Ultrasound revealed suspected fibrous adhesions within the urinary bladder lumen connecting the dorsal and ventral bladder wall creating a septum. This was confirmed cystoscopically 4 weeks after surgery.

TREATMENT AND OUTCOME

Cystoscopic-guided laser ablation was performed to incise abnormal tissue connecting the ventral and dorsal bladder wall using a holmium:yttrium-aluminum-garnet laser. Three weeks later, ultrasound revealed adhesion resolution though mild pollakiuria and stranguria persisted. Oxybutynin was prescribed and clinical signs resolved. At 27 months after ablation, hematuria occurred with recurrent cystoliths. These cystoliths were removed by percutaneous cystolithotomy, documenting a cystoscopically normal bladder wall. The patient had normal urination for 55.5 months after ablation, with normal bladder wall thickness on ultrasound repeated at 27 and 36 months after ablation.

CLINICAL RELEVANCE

To the authors' knowledge, an adhesion creating a septum between the dorsal and ventral bladder wall has not been previously reported as a complication after cystotomy in any species and should be considered as a cause of persistent lower urinary signs after surgery. Ultrasound identified the lesion in this dog. Because bladder abnormalities can develop quickly after surgery, ultrasound might be considered if urine testing is not supportive of infection. Cystoscopic-guided laser ablation was a successful minimally invasive treatment in this case.

Pseudomembranous Cystitis: An Uncommon Ultrasound Appearance of Cystitis in Cats and Dogs

In veterinary medicine, pseudomembranous cystitis (PC) is a rare condition described only in cats. The purposes of this retrospective study were to describe ultrasound features of PC in cats and dogs, predisposing factors, comorbidities and outcomes. Cats and dogs with an ultrasonographic diagnosis of PC were included in the study. The bladder ultrasound findings that were recorded were: pseudomembranes' characteristics, abnormalities of the bladder's wall and content and anomalies of the pericystic peritoneal space. Ten cats and four dogs met the inclusion criteria. Four pseudomembrane adhesion patterns were described. The presence of pseudomembrane acoustic shadowing was observed in the 60% of cats. A total of 80% of the cats included were presented for urethral obstruction (UO) and/or had at least one episode of UO in the previous 2 months. Thirteen patients out of fourteen received only medical therapy, and all of them survived. PC is a rare disorder in cats and dogs and there are some ultrasonographic differences between the two species, suggesting a greater severity of the pathology in cats. Chronic cystitis and UO may have a potential role in the development of feline PC. Finally, the medical approach can be a non-invasive and effective approach for PC.

Feline abdominal ultrasonography: What's normal? What's abnormal? Renal pelvis, ureters and urinary bladder

PRACTICAL RELEVANCE

Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. Ultrasound examination of the urinary tract provides important information useful in the investigation of several conditions including ureteral obstruction and cystitis.

CLINICAL CHALLENGES

Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even for the experienced ultrasonographer, differentiating between incidental findings, such as lipid droplets in the bladder, and pathological changes can be challenging.

AIM

This review, part of an occasional series on feline abdominal ultrasonography, discusses the ultrasonographic examination of the normal and diseased renal pelvis, ureters and urinary bladder. Aimed at general practitioners who wish to improve their knowledge of and confidence in feline abdominal ultrasound, this review is accompanied by high-resolution images and videos available online as supplementary material. Ultrasound examination of the kidneys and perinephric space was discussed in an article published in May 2020.

EQUIPMENT

Ultrasound facilities are readily available to most practitioners, although the use of ultrasonography as a diagnostic tool is highly dependent on operator experience.

EVIDENCE BASE

Information provided in this article is drawn from the published literature and the author's own clinical experience.

Ultrasonographic Diagnosis of Urachal Anomalies in Cats and Dogs: Retrospective Study of 98 Cases (2009-2019)

This retrospective study investigated the prevalence of different urachal anomalies (UA) in cats (n = 60) and dogs (n = 38) and their association with clinical symptoms and urinalysis alterations. Among UA, the vesicourachal diverticulum was the most prevalent UA diagnosed in both cats (96.7%) and dogs (89.5%): the intramural vesicourachal diverticulum was diagnosed in 76.7% of cats and 71.1% of dogs, followed by extramural vesicourachal diverticulum (20.0% and 18.4% respectively). In both cats and dogs, bladder wall diffuse or regional thickening was the most prevalent alteration. The most common alterations of the urinary bladder content were urolithiasis sediment in cats (33.3%) and in dogs (31.6%). Dogs with UA were more often asymptomatic (p = 0.01). No difference was found in cats. Stranguria, hematuria, and urethral obstruction were the most frequently reported clinical signs, while hematuria and leukocyturia were the most prevalent abnormalities at urinalysis. In conclusion, our study confirmed UA as uncommon, and often incidental findings, with a high prevalence of animals without clinical signs.

Successful medical management of pseudomembranous cystitis in three cats with lower urinary tract obstruction

CASE REPORT

The present case series describes the clinical course and outcome of three cats diagnosed with pseudomembranous cystitis. This is an uncommon presentation of lower urinary tract obstruction but can be easily be identified by ultrasonography, revealing severe bladder wall thickening and thin hyperechoic luminal strips. The condition can be secondary to severe bacterial urinary tract infection. All cats were successfully treated with medical management only, mainly based on antimicrobials and individualised supportive therapy.

CONCLUSION

Further evaluation of this condition is necessary in order to determine potential underlying aetiologies, pathophysiological mechanisms and the most appropriate standardised treatment.

Membrane-like structure in the urinary bladder neck of a young cat: diagnosis and treatment using balloon dilatation and a balloon-expandable metallic stent

Case summary

A 33-month-old, spayed female domestic shorthair cat was referred to the Animal Health Trust for the investigation of urinary incontinence and straining to urinate. A membrane-like structure was detected in the bladder neck, which caused partial obstruction of the urinary bladder. A combination of different imaging techniques, including ultrasonography, radiography, CT and fluoroscopy, was essential in the diagnosis, surgical planning and treatment of this intravesicular stricture. During retrograde vaginourethrocystogram, unexpected subcapsular accumulation of contrast medium was seen around both kidneys on radiographs and confirmed with CT. Three different treatments were performed, including surgical debridement, balloon dilatation and placement of a self-expanding metallic stent across the stricture. Histopathology of the membrane was unable to differentiate whether the lesion was congenital or acquired. No urinary incontinence was observed 5 months after placement of the metallic stent.

Relevance and novel information

This is the first reported case using fluoroscopic-guided balloon dilatation of the bladder neck for the treatment of a bladder neck stricture. Presence of renal subcapsular contrast medium secondary to a retrograde vaginourethrocystogram due to partial obstruction at the bladder neck in a cat has not been previously described.

ASSOCIATIONS BETWEEN ULTRASOUND AND CLINICAL FINDINGS IN 87 CATS WITH URETHRAL OBSTRUCTION

Urethral obstruction is a life-threatening form of feline lower urinary tract disease. Ultrasonographic risk factors for reobstruction have not been previously reported. Purposes of this retrospective cross-sectional study were to describe urinary tract ultrasound findings in cats following acute urethral obstruction and determine whether ultrasound findings were associated with reobstruction. Inclusion criteria were a physical examination and history consistent with urethral obstruction, an abdominal ultrasound including a full evaluation of the urinary system within 24 h of hospitalization, and no cystocentesis prior to ultrasound examination. Medical records for included cats were reviewed and presence of azotemia, hyperkalemia, positive urine culture, and duration of hospitalization were recorded. For medically treated cats with available outcome data, presence of reobstruction was also recorded. Ultrasound images were reviewed and urinary tract characteristics were recorded. A total of 87 cats met inclusion criteria. Common ultrasound findings for the bladder included echogenic urine sediment, bladder wall thickening, pericystic effusion, hyperechoic pericystic fat, and increased urinary echoes; and for the kidneys/ureters included pyelectasia, renomegaly, perirenal effusion, hyperechoic perirenal fat, and ureteral dilation. Six-month postdischarge outcomes were available for 61 medically treated cats and 21 of these cats had reobstruction. No findings were associated with an increased risk of reobstruction. Ultrasonographic perirenal effusion was associated with severe hyperkalemia (P = 0.009, relative risk 5.75, 95% confidence interval [1.54-21.51]). Findings supported the use of ultrasound as an adjunct for treatment planning in cats presented with urethral obstruction but not as a method for predicting risk of reobstruction.